甘薯抗薯瘟病的水杨酸与活性氧的代谢变化

研究不同抗性甘薯品种受薯瘟病菌侵染后水杨酸(SA)和活性氧(ROS)的代谢变化.结果表明,感染薯瘟病菌12 h后甘薯叶片中SA含量增加,增加量与品种抗性呈正相关;接菌后过氧化氢(H2O2)含量增加,过氧化氢酶(CAT)活性下降,抗病品种变化幅度大于感病品种;接菌后抗病品种提高了与产生H2O2相关的酶过氧化物酶(POD)、超氧化物歧化酶(SOD)的活性,而感病品种与此相反,积累H2O2的能力下降,影响系统获得抗性(SAR)的建立.     

Accumulation and distribution of free folic acid content in red beet (Beta vulgaris L.)

Among vegetable plants, red beet contains a relatively high level of the B vitamin folic acid. Although many leafy green vegetables contain high levels of folic acid, red beet is consumed primarily as a root vegetable. Folic acid levels have been quantified in various vegetable plants, but little information exists regarding the accumulation and distribution of this vitamin in plant tissues. The objective of this study was to characterize free folic acid content (FFAC) in shoot and root tissue during growth of two red beet inbreds. Experiments were conducted in a greenhouse during 1993, 1994 and 1995. Two inbreds, W384 and W357, were planted in randomized complete blocks and shoot and root tissues were separately harvested at 60, 80, and 100 days after planting (DAP). Significant differences between years, tissue portions, and among harvest dates were detected, however, similar patterns in FFAC accumulation and distribution were observed between inbreds and years. FFAC in shoot tissue was significantly greater than root tissue for both inbreds. Accumulation of FFAC was linear for both inbreds across harvest dates for root tissue but not for shoot tissue. FFAC accumulation in shoot tissue increased sharply from 60 to 80 DAP but decreased sharply from 80 to 100 DAP. These results demonstrate that FFAC accumulates differentially in root and shoot tissue in a red beet plant. Maximum folic acid levels in shoot tissue are achieved prior to those in root tissue.     

Effects of nitrogen,phosphorus and potassium fertilizer treatments on weight loss and changes in chemical composition of potato tubers stored at 4°C

Summary Pot and field experiments were carried out to test fertilizer treatments on the behaviour of potato tubers stores at 4°C and ≥90% relative humidity for 6 months. Weight losses (separated into water and dry matter) were enhanced after N and K fertilization and decreased by increasing P supply. Glucose and fructose contents were reduced at harvest by high N-fertilizer rates compared to no or low fertilization, but throughout storage reducing sugar accumulation was increased, sucrose reduction was decreased and ascorbic acid was increased. K fertilization affected the chemical composition of the tubers somewhat similar to that of nitrogen fertilization. High initial nitrate content of the tubers seemed to be increased and low nitrate values were decreased during storage. The tubers from pot experiments showed similar changes but of greater magnitude.     

An artificial neural network approach to prediction of the colorimetric values of the stripped cotton fabrics

This paper presents an artificial neural network (ANN) modeling by Levenberg-Marquardt (LM) algorithm for predicting the colorimetric values of the stripped cotton fabrics dyed using commercial reactive dyes. Achieving the expected efficiency in the application of stripping process is a very important aspect for the success of the reproduction. In the study, the predictions of L* and ΔE colorimetric values of stripped cotton samples for different stripping applications by artificial neural network are reported. We set up different network structures with different number of nodes in the hidden layer, the number of inputs and MSE of results as stopping criteria in order to get the best fitting model. According to the result of the best neural network models predicting L* and ΔE, we achieved 97 % of R for both of them. We are able to predict the L* value of the stripped samples using some working parameters as inputs with only 1.2 % error. We think that our results are very promising and the predictions of L* and ΔE values of stripped samples before applying any process are possible using the ANN model set up in the study, especially for L*.     

A rapid screening technique for drought resistance in potato (Solanum tuberosum L.)

Summary The reduction in growth in the dark of leaf dises floated over polyethylene glycol 6000 solution of water potential −0.4 MPa, relative to the growth of similar leaf dises floated over water for the same period, varied in the range 10–87% in 28 genotypes. The growth reductions in the genotypes tested were in general agreement with what is known about their drought resistance. Publication No. 906, Central Potato Research Institute, Simla.     

Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

Summary Two German cultivars differing in blackspot susceptibility were grown in pots in 1998 and 1999 under control and water stress conditions. Blackspot susceptibility of the tubers was defined as oxidative potential. The effect of free tyrosine, cysteine, phenylalanine, chlorogenic and ascorbic acid on the oxidative potential was analyzed. A high concentration of ascorbic acid led to a decrease in the oxidative potential after harvesting in 1998. No correlation was found between oxidative potential and free tyrosine, phenylalanine or cysteine, respectively. Chlorogenic acid content increased during storage and gave a significant correlation with discoloration, showing that it can have an effect on the oxidative potential of the tuber greater than previously thought. Supplementing freeze-dried potato samples with pure chlorogenic acid increased the oxidative potential. Oxidative potential seems to depend on a series of chemical compounds, and their content is affected by factors including annual variations, cultivar, water availability and storage.     

A diet based on wheat bread baked with lactic acid improves glucose tolerance in hyperinsulinaemic Zucker (fa/fa) rats

In the present study, the objective was to evaluate the long-term metabolic impact of adding lactic acid to a bread-based diet in obese, hyperinsulinaemic Zucker (fa/fa) rats. All diets were based on a white wheat bread, and the lactic acid was added either prior to, or after the baking process. In addition, a diet with addition of Lactobacillus plantarum 299v was included to investigate the possible impact of probiotic lactic acid bacteria, in the absence of lactic acid. The intervention period was fourteen days and oral glucose tolerance tests (OGTTs) were performed before and after the intervention. Glucose, insulin and glucagon were measured during both OGTTs. Other parameters studied were blood lipids (total cholesterol and triglycerides) and liver cholesterol. The intervention period with the wheat bread baked in the presence of lactic acid improved glucose tolerance as judged from a 51% reduction (P=0.007) in the total glycaemic area. In contrast, there was no such improvement with the diet where lactic acid was added after baking or with addition of probiotic bacteria. No differences were seen between groups in insulin, blood lipids or liver cholesterol following the intervention. It is concluded that bread baked in the presence of lactic acid improves glucose metabolism in obese and hyperinsulinaemic Zucker rats.     

A comparative study of phenylpropanoid metabolism in gamma irradiated and unirradiated potato tubers

Summary Phenylpropanoid metabolism in gamma irradiated potato tubers was studied by examining the pattern of incorporation of radioactivity from U-¹⁴C phenylalanine into caffeic acid. chlorogenic acid and the coniferyl and sinapyl moieties of lignin. During a post-irradiation period of 21 days a depletion in chlorogenic acid was observed. This is a result of its impaired synthesis as well as an accelerated conversion of chlorogenic acid to ferulic and sinapic acids and their deposition in lignin. The results offer an explanation for the lower level of chlorogenic acid invariably observed in irradiated potato tubers.     

The involvement of phenolics and phytoalexins in resistance of potato to soft rot

Summary Phenolics, for example chlorogenic, caffeic and ferulic acid, and phytoalexins, such as rishitin and phytuberin, were identified in potato tubers cv. Kufri Chandramukhi. The tissue of healthy tubers contained no detectable phytoalexins but did contain phenolics. The levels of these compounds were correlated with soft rot development. The rotting tissue either was free of these groups of compounds or had low concentrations. The wound periderm formed as a result of recovery from injury and infection contained high levels of the compounds. Much higher concentrations were detected at lower storage temperatures when oxygen supply was adequate. Antibacterial properties of the phenolics identified were tested againstErwinia carotovora which was inhibited by chlorogenic, caffeic and ferulic acids. The three phenolics were more effective together, in proportions in which they occurred in wound periderm, than individually. It was observed that none of these phenolics could inhibit pectolytic enzymes ofE. carotovora.     

河北省夏玉米苗期根病发生现状及病原初探

2008～2009年对河北省中南部夏玉米主产区玉米苗期根病进行调查发现,玉米苗期根病在河北省夏玉米主产区普遍发生,各地区平均病株率在73.9%～100.0%,病情指数在14.0～30.9.对各地区玉米根病病株进行病原菌分离和形态学鉴定,河北省夏玉米苗期根病主要因真菌引起,且由多种病原菌复合侵染,分离到的主要病原菌有藤仓赤霉复合种、离蠕孢菌、腐霉菌、丝核菌和禾谷镰孢菌,不同地区主要病原菌的种类存在差异.对优势病原菌进行致病力测定发现,离蠕孢菌致病力最强,且能引起植株矮化,严重影响地上部植株的生长.     

Nutrient Content of Four Edible Wild Plants from West Africa

Non-cereal plant foods in the Western Sahel of Africa contribute significantly to the diets of local residents, especially during periods of grain shortages. In this paper, we analyze four such plant foods including diyan kwakwa (nut of coconut palm, Cocos nucifera L.), muricin giginya (young shoot of Borassus aethiopum), tsamiya biri (fruit of the tree, Tamarindus indica), and yari (a mixture of lichens, mainly Rimelia reticulate) that grows on ebony trees (Diospyros mespiliformis). They were analyzed for their content of amino acids, fatty acids, and minerals. Although diyan kwakwa contained the highest protein content (27.1%), its protein quality fell below the WHO standard in 3 of 8 essential amino acid categories. Yari and muricin giginya contained moderate levels of good quality protein. Only diyan kwakwa contained calorically significant amount of total fatty acid (24.7%); however, none of the plants contained useful amounts of the essential fatty acids, linoleic acid, or α-linolenic acid. All four plants contained useful amounts of zinc (> 12 μg/g dry weight), while yari contained the most calcium (14.7 mg/g dry weight) and iron (1.41 mg/g), and diyan kwakwa the most copper. All the four plant foods contained lesser amounts of magnesium, molybdenum, or selenium. These data indicate that the four plants contain useful amounts of various essential nutrients that could supplement the diets of populations inhabiting the Western Sahel.     

小麦属植物叶绿体基因组结构的比较分析

为了从叶绿体角度解析小麦属植物的起源进化关系,以14个小麦属植物叶绿体基因组为对象,利用比较基因组分析方法,比较了小麦属植物的叶绿体基因组基因含量、序列变异、结构特性、进化关系和RNA编辑的异同。结果发现,14个小麦属植物叶绿体基因组大小相近,结构特征比较保守,但基因数量存在一定的差异,主要是由于tRNA的数目不一致引起的;IR区的伸缩分析发现硬粒小麦和乌拉尔图小麦在IRb-SSC边界基因存在明显的差异,其他麦类作物间差异很小;基于叶绿体全基因组的系统进化分析发现,有AABB基因型的物种聚在一起,而AAGG型的单独为一支,基本反映了其系统进化关系;对这14个叶绿体基因组的RNA编辑位点进行了预测和比较分析,发现有35个编辑位点在所有小麦属物种中均发生,同时还鉴定到多个物种特异的编辑位点,为从RNA编辑角度解析小麦属植物的系统进化关系提供了重要数据。     

OsPHR2对小麦酸性磷酸化酶活性和根系土壤有机酸含量的影响

为了明确水稻低磷胁迫转录因子OsPHR2对小麦酸性磷酸化酶活性、根系土壤有机酸含量和根系活力的影响,以转OsPHR2小麦纯合株系和受体对照为试验材料,在不施磷（低磷）、施易溶性磷（0.200 g·kg^-1,KH₂PO₄为磷源）和施难溶性磷（0.200 g·kg^-1,以AlPO₄为磷源）3个处理下开展转OsPHR2小麦酸性磷酸化酶活性、根际土壤有机酸含量和根系活力的研究。结果表明,拔节期、抽穗期和灌浆期,在低磷和施AlPO₄处理下2个转OsPHR2小麦株系旗叶和根部酸性磷酸化酶活性均显著高于受体对照;施KH₂PO₄处理下,2个转基因株系旗叶酸性磷酸化酶活性在抽穗期和灌浆期均显著高于对照,根部在抽穗期显著高于对照,其他时期差异均不显著。随着小麦生育进程,小麦根际土壤草酰乙酸、草酸、乙酸、丙二酸和柠檬酸等有机酸含量逐渐增加。拔节期和抽穗期,在低磷、施AlPO₄和施KH₂PO₄处理下转基因系OsT5-28根际土壤五种有机酸含量均显著高于对照。转基因小麦根际土壤有机酸含量较对照的提高幅度在拔节期或抽穗期较大。三种处理下转基因系OsT5-28根系TTC还原力在三个时期均显著高于对照。这说明低磷胁迫下OsPHR2可提高小麦酸性磷酸化酶活性和根系活力,促进根系有机酸的分泌,增加分泌量,从而提高小麦磷素吸收效率。     

Amino acid composition,relative nutritive value and in vitro protein digestibility of several Philippine indigenous legumes

This study demonstrates variability in amino acid composition among accessions of several Philippine indigenous legumes. Moreover, two accessions ofD. lablab were identified to have high level of methionine (>2%). Methionine was identified as the first limiting amino acid with leucine, and threonine as the second limiting amino acids for most legumes studies.The IVPDs of the legumes under study ranged from >70 to 79%. Raw mature seeds had relatively low RNVs of 11 to 68% which increased to 68 to 94% and 51 to 89% after boiling and roasting, respectively.     

Soluble proteins and isoesterases as taxonomic markers tested on nine wildSolanum species and eight Slovakian potato varieties

Summary Attempts have been made to differentiate 9Solanum species and 8 Slovakian cultivars ofS. tuberosum using soluble proteins, isoesterases and antigenic properties of tuber proteins. Soluble proteins were shown to possess the highest diagnostic value in discriminating between individual species and varieties.S. brevidens of the subsectionEstolonifera deviated from the rest of the species belonging to the subsectionPotatoe. The electrophoretic profiles and immunological responses of individual species only partially correlated with their taxonomic positions. The highest similarity was observed between the pairs of speciesS. bulbocastanum, S. stenotomum, S. maglia-S. phurea andS. gourlayi-S. vernei. It was possible to differentiate also between individual potato cultivars or between their groups according to both soluble protein and isoesterase patterns.     

The fermentation of trahanas: a milk-wheat flour combination

The fermented food, trahanas (a milk-wheat flour combination prepared in Greece), was studied to determine the microbiological and chemical changes that occur during fermentation. It is a lactic acid bacterial fermentation in whichStreptococcus lactis, Streptococcus diacetylactis, Leuconostoc cremoris, Lactobacillus lactis, Lactobacillus casei, Lactobacillus bulgaricus andLactobacillus acidophilus play the major acid- and aroma-producing role. The whole fermentation lasts about 50 hours. The pH of the final dried trahanas was 4.07–4.75, the acidity 0.60–1.00%, the moisture content 8.6–11.5% and the protein content 10.4–13.6%. The product offers possibilities as an increased nutritive value or high-protein food.     

Propagation of potato by shoot tip culture in petri dishes

Summary A method is described for propagating potato shoot tips with liquid culture in petri dishes. With cv: Exton, Pontiac, Kennebec and Sebago multiplication rates could exceed 8-fold every 8 weeks. The petri dishes can be packed so as to accommodate large numbers of multiplying tips in a small space.     

In vitro induction of potato tuberization by organic acids

Summary Potato microtubers are usually induced in media containing growth regulatory, typically cytokinins and growth retardants. However, since these substances may imbalance the physiology of the cultured explants and cause adverse carry-over effects on the subsequent performance of the microtubers, the potential acid-induction of in vitro-mass tuberization was investigated as an alternative. For this purpose, a range of explant types (stolons, single-node or apex-containing multinodal sections), organic acids (acetic, propionic, ascorbic, acetylsalicylic or salicylic acid), and photoperiods (continuous dark, 8 or 16 h photoperiod) were established. Gellified medium or raft membranes on liquid medium were also tested. Although variations due to explant type, photoperiod, organic acid supplemented, and medium type were found, all organic acids tested under the different experiments caused tuberization. Multiple tuber formation or bigger tubers did not develop on multinodal explants. In terms of tuberization rate and mean tuber weight, gellified medium performed better than liquid medium with rafts. The recently established role of the salicylic and acetylsalicylic acids on tuberization is corroborated by our system. The results with the acetic, propionic and ascorbic acids show that in vitro hormone-free tuberization can be easily and rapidly achieved.     

Nutritional potential ofVigna minima (Roxb.) Ohwi and Ohashi:

Quantitative variation in different fractions of seed proteins and their amino acid levels in populations ofVigna minima (Roxb.) Ohwi and Ohashi and inV. umbellata cv. IC 1568 — the rice bean — were investigated. Globulin I fraction, together with globulin II, constitutes 38 to 54 per cent of the total seed protein. The alkali soluble (glutelin) fraction is the second largest fraction. Both these fractions show broad range of variation, suggesting a broad genetic base. The profiles are population specific; the coastal population, which contains higher seed protein also possesses maximum levels of globulin I and glutelin fraction suggesting its potentiality for breeding lines with high protein content, high nutritive value, and salt tolerance. Protein content is positively correlated with globulin I and glutelin fractions, which are in turn positively correlated with each other. The amino acid profiles are specific not only to the fractions but also to the populations. The range of variation in the levels of all amino acids in different fractions is broad suggesting substantial genetic diversity. The average levels of lysine and sulphur amino acids are high in globulin I and glutelin fractions.     

Antioxidant in Mango (<Emphasis Type="Italic">Mangifera indica</Emphasis> L.) Pulp

This work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of β-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); β-carotene from 661.27 (Palmer) to 2,220 μg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.